Controlling mechanism for oil burners



Oct. 30, 1928. 1,689,803

0. c. SCHROEDER CONTROLLING MECHANISM FOR OIL BURNERS Filed. March 12, 1927 3Sheets-Sheet 1 Ill 3'Sheets-Sheet lll/lllllll/l/l/I/l/II/I/ kzzflz%whwzwzzzzzzzzzzz WZZQZQQQQZZZZZZZZZZZZZ? O.C.SCHROEDER CONTROLLING MECHANISM FOR OIL BURNERS Filed March 12, 1927' Oct. 30, 1928.

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O. C. SCHROEDER CONTROLLING MECHANISM FOR OIL BURNERS Filed March 12, 1927 3 Sheets-Sheet 5 fizmzz Z67: OscarCaZra 8167" Patented Oct. 30,1928. I

OSCAR C. SCHROEDER, OF CHICAGO, ILLINOIS.

CONTROLLING MECHANISM FOR OIL BURNERS.

Application filed March 12, 1927. Serial No. 174,782.

My primary object is to provide improvements in electrical controlling mechanism for oil burners, to the end that danger in the operation of the apparatus will be reduced to the minimum, if not entirely overcome.

More specifically stated, certain of my objects are to avoid possibility of the generation of a large body of explosible gas in a furnace equipped with the burner and which if the same were ignited would produce an explosion liable to result in damage; to provide improvements to the end that the discharge of oil from the burner must be substantially simultaneous with the production of a gasigniting flame or spark, which ensures ignition of the vaporized fuel substantially simultaneous with the discharge from the burner, thereby avoiding explosions which sometimes occur in furnaces equipped with oil burners of such construction that the discharge of oil from the burner may take place independently of the conditioning of the igniter means; to provide improvements to the .end that should the oil supply fail, the opera.-

tion of the mechanism of the. burner will be automatically arrested; to provide improvements to the end that should the flow of cureration simultaneously, or practically simultaneously, therewith; and other objects as will be manifest from the following description.

Referring to the accomp anyingdrawings in which I have chosen to illustrate my invention as applied to'a burner of the type comprising a motor which operates to discharge the oil from the burner into a furnace to be-hcated Figure 1 is a view in elevation, with certain parts sectioned, of the lower portion of a. furnace structure equipped with a burner of the type referred to controlled by mechanism constructed in accordance with my invention. Figure 2 is a View in vertical sectional ele- .vation of a heat-controlled electrical switch device forming one of the elements of the controlling mechanism referred to and illustrating the switch in closed condition. Figure 3 is a similar view of the switch portion of the device of Fig. 2 showing the switch in open condition; and Figure 4, a view somewhat in the nature of a diagram ofthe burner and the controlling mechanism therefor, including the electrical circuits in which the varlous parts of the mechanism are interposed.

By way of explanation of the construction of the particular burner in connection with which I have chosen to illustrate my invention, it may be stated that it is of the type above referred to and disclosed in U. S. Letters Patent No. 1,505,607, granted August 19, 1924, to Oscar C Schroeder, it being suliicient, for the present application, to state that the burner head represented at 10 and which extends upwardly through a central opening 11 in the bottom 12 of the furnace 13, is mounted upon the upper end of the armature shaft of a vertically disposed motor 201, to be driventhereby and spray laterally outwardly into the bottom portion of the chamber 13 oil delivered thereto through the armature shaft, by virtue of the rotation of the latter, this shaft extending downwardly into a receptacle 14 to be fed with oil therefrom and supplied to the receptacle, in any suitable way, through a pipe 15, it being understood that oil is discharged into-the furnace 13 through the burner only when the motor is running, the motor being supplied with current as hereinafter described.

Located to one side of the burner proper, is a pilot tube 16 adapted to be supplied with gas through a pipe 17 leading to a source of constant supply and controlled through the medium of electrical cont-rolling mechanism represented generally at 18 and hereinafter described. The pilot tube 16 is so disposed that the flame produced by the igniting of the gas issuing therefrom, will ignite the fuel discharged from the burner 10, there being associatedwith this pilot tube 16 electrical igniter means comprising the two electrodes 19 and 20 which are spaced apart to present a spark ap intersecting the upward flow of the gas rom the tube 16, these electrodes becomprises a hollow body 23 shown as of tubular form and closed except for an opening in its lower end at which it communicates with a pipe 24.. The side walls and top of the hollow body 23, are preferably constructed of relatively thin metal, to permit of the quick heating of the contents of the'member 23, by the subjection thereof to the heat of the flame produced by the oil in burning as it issues from the burner, and the cooling of such contents, by the action of the atmosphere, upon the extinguishment of the flame. The pipe 24 shown as carrying the member 23, is carried by, and communicates with a chamber 25 in a brackethead 26 supported on a rod 27 in turn carried by an arm 28 supported, and vertically adjustable on, a post 29 forming, with other posts 30 and 31, legs for supporting the burner structure. The chamber contains a hollow member 32 I 25 l1aving a depending, restricted, open-ended, cylindrical portion 32 opening at its lower end into the chamber 25 and at its upper end into the space 32 provided by the member 32, the space 32 opening at its upper end to the atmosphere through an opening 32 in the side wall of the member 32 communicating with a passage 32 inthe wall of the chamber 25. Reciprocable in the cylinder 32 is a piston 33 containing passages 33 85 and 33 extending lengthwise therethrough,

the lower endofthe passage 33* andthe upper end of passage 33 having=valve seats for downwardly and upwardly opening check-valves 34 and 34, respectively, the

seating-springs for which are represented at 34 and 34, respectively. The piston 33 is pivotally connected with the lower end. of a link 35, the upper end of which extends through. an opening in a plate 32 fitting .45 down on the top of member 32, and pivotally connects with a lever 36 pivoted at one end at 36*" on a stud 32 rising from the plate 32. The other end of the lever 36 is provided with an arm 36", pivoted between its ends at 36 to the lever 36, the lower end of the arm 36 carwhich the switch arm 37" is movable, the referred toisshown rying a roller 36 and its upper end connected with-one end of. a coil spring 36the other end of which connects with a stud on the lever 36. The roller-equipped end of arm cooperates with a switch represented generally at 37 and comprising a contact 37 terminating in a rocking switch arm 37 pivoted on the contact 37, and a fixed contact 37 into and out of engagement with 36 to the position shown in Fig. 3.

at this point. Upon the application of heat I to the meinber 23, as for exampleby the flame created by the burner 10 in operating,

the air in the member 23 becomes heated, thereupon expanding and producing a pressure within the chamber 25 causing the piston 33 to rise and rock the switch arm 37" controlled thereby to a position in which the circuit is broken at this point (Fig. 3). The spring 34 is so tensioned that so long as the temperature of the member 23 rises, or, after rising, remains substantially constant, the piston 33 will be held in raised position and the circuit through the switch device 37 brokenyexcess pressure generated in the member 23 escaping therefrom into chamber 25 and thence past valve 34* and through port 32 and passage 32 to the atmosphere. In other words the construction referred to, by properly tensioning the spring 34, imprisons, against escape, air up to a certain pressure sufficient to hold the piston 33 raised and the switch device in circuit-breaking position, excess pressure generated in receptacle 23 escaping to the atmosphere past valve 34*.

Upon the cooling of the receptacle 23, which results, upon the extinguishment of the flame produced by the burner, this cooling effect eing augmented by providing a flue 45 shown in Fig. 1 for the upward circulation of air around the member 23, the air in the member 23 contracts with the result that the piston 33 lowers returning the switch device con nected therewith, to the circuit-closing position represented in Fig. 2,and when the pres- 3 sure of the air in the member 23 becomes reduced below a predetermined degree, deter- Wmined by the tension of the spring 34", air from the atmosphere will be sucked into it by passing through passage 32, port 32, pistonpassage 33, and past valve 34.

The particular construction of electricalmechanism illustrated generall at 21 and hereinbefore referred. to comprises a simple transformer operating to step up the current to a relatively high voltage and comprising the primary coil 46 and the secondary coil 47 to the terminals of whichlatter the electrodes 49, respectively.

The electrical gas-controlling mechanism represented generally at 18 and hereinbefore as comprising a solenoid 0011 50 mounted upon a ing member 51 closed at its upper en plug 52, and a sliding core 53, the lower'end ofwhich and represented at 54 forms avalve controlling the passage of gas from a conhollow iron supportduit 55 in the member 51 and supplied with gas through the pipe 17, to a conduit 56 opening into the member 51 and communicating with the pilot tube 16, the core 53 when the solenoid 50 is. deencrgized, shutting off the flow of gas to the pilot tube, but permittin it to flow thereto when raised by energizing 1%118 solenoid.

The electrical mechanism also comprises a time-switch which may be of any suitable construction, that shown comprising a coil 57 adapted to be heated by the passage of current therethrough; a rocking mercury-tube switch device 58 of common construction, the electrodes of which are represented at 59 and 60, the base-portion 61 of this device being pivotally supported at 62 and its opposite end formed to present a shoulder 63, and a thermostatic element 64 cooperating with the coil 57 and switch 58. The thermostatic element 64 which is preferably formed of two flatwise opposed strips 65 and 66 of metal having different coefficients of expansion, is positioned lengthwise of, and closely adjacent to, thecoil 57, and in the normal, cool, condition of the element 64, it extends into the position shown in Fig. 4 thereby forming a support for the switch device 58 which, in circuit-closing position, rests at its shoulder 63 upon the upper end of the member 64, the member 64, upon becoming heated by the coil 57, to a predeter mined degree, deflecting to the left in Fig. 4

and releasing from the shoulder 63, permitting the switch device 58 to rock downwardly to a position in which the mercury disengages from the electrodes 59 and 60 and breaks the circuit through this device, the shoulder 63, in this 0 eration, dropping upon a lug 67 on the mem er 64 which serves to limit downward rockin movement of the switch 58.

The electrical mechanism also comprises a relay-controlled switch by which the current to the motor is directly controlled. Thismechanism is represented generally at 68 and is shown as compr1s1ng a rockmg mercury switch devlce 69 of the same general construction as the switch device 58, its electrodes being represented at 70 and 71. The switch device 69 is controlled by a relay device comprlslng electro-magnets 72 and 73, the coils of these magnets being represented at 74 and 75, respectively. Extending below the pole pieces of these magnets is an armature 76,

which is shown as connected, through the me dlum of links 77 and 78' and a rocking lever 79, with the switch device 69, the arrangement of these parts being such that when the armature- 76 is raised to the position shown in Fig. 4 by theenergization of both coils 74 and 75, the switch device 69 will be tilted to the circuit-closing position shown in Fig. 4

and remain in this position so long as the armature 1s ra1sed, but as soon as the armature 76 ceases to be held in raised position these parts will automatically move to a position in which the circuit through the switch device 69 is broken, It may be here stated that the strength of neither of the magnets 7 2 and 73 is suflicient to alone lift the armature 76 from lowermost position for rocking the switch 69 to circuit-closing position, it requiring the energization of both of these magnets to effect this operation. However, both of these magnets are of such strength that either is capable of holding the armature 76 in the ra1sed position shown in Fig. 4, with the switch 69 closed.

The arrangement shown also involves a room thermostat which,by way of example, may be located in a room to be heated from the furnace 13 and which is provided to control the operation of the burner responsive to temperature changes in the room. Such a thermostat is represented at 80 and is shown of a common well-known construction involv- {ing a tiltable mercury tube switch device 81 degree, the mechanism shown comprising generally stated aBourdon tube 86 in communication with a pipe 87 which would open into the interior of the boiler, and a tiltable mercury switch device 88, of the same general construction as the switch 58, operatively connected with the free end of the tube 86, as through the linkage 89 and 90 to be rocked responsive to themovements of the tube 86, the electrodes of this switch device being represented at 91 and 92, respectively.

It may be here stated that the arrange- "ments of the parts of the room thermostat 80 and the boiler thermostat 85 are such that when the temperature of the room drops to a predetermined degree the mercury in the device 81 will close the circuit at the electrodes 82 and 83, and when pressure in the boiler is below a predetermined degree the mercury in the device 88 will close the circuit at the electrodes 91 and-92.

Referring. now to the various circuit arrangements shown in Fig. 4, the line or service wires are represented at 93 and 94. A wire 95 leads from the wire 93 to one of the terminals of the motor 201, thewire 95 being connected, between its ends, with a wire thermostat 85.

by a wire 98, with one end of the coil 75. The wire 94 is connected by a wire 99, with the electrode 59 of the switch device 58, there being interposed in this wire 99, in series, the electrodes 82 and 83 of the room thermostat 80 and the electrodes 91 and 92 of the boiler The electrode 60is connected by awire 100 with the electrode 71 of the switch device 69, the other electrode of which, 70, connects by a wire 101 with the other terminal ofthe burner motor 201. The wire 100 connects, between its ends, with a wire 102 which is connected with the other terminal of the coil 74, the wire 100 between its connection with the wire 102 and the electrode 71, being connected with a wire 103 which connects with the terminal 37 of the switch device 37, the other terminal 37 of this switch device being connected with a wire 104 which connects with the other end of the heating coil 57. A wire 105 connects with the wire 104 between its ends andwith the other terminal of the coil 75. The coils and 46 are arranged in parallel with the heating coil 57 and winding 75, a wire 106 leading from the wire 104 to one of the terminals of the coil 50 and also, by a branch wire 107, to one of the terminals of the coil 46; and a wire 108 leading from the wire 96 to the other terminal of the coil 50, and, by a branch wire 109, to the other terminal of the coil 46.

The Various parts of the apparatus shown are represented in the condition they. assume when the temperature in the room equipped with the thermostat 80 is below the temperature desired to be maintained therein; the pressure in the boiler is below the maximum pressure to be attained in the boiler, and the burner has just started into operation and has not been operating sufficiently long to operate the mechanism 22 (Figs. 2 and 3) to circuit-breaking position, assuming that the ap aratus is properly functioning.

n such condition of the parts of the apparatus, the circuit is closed at the contact devices 81 and 88 of the room and boiler therm'ostats, the switch 81 in closing, completing a circuit from the wire 93 through the wires 95 and 96, through heating coil 57, wire 104, contacts 37 a and 37 of the switch device 37, wires 103 and 100, through electrodes and 59, wire 99 and through the boiler thermostat 85 and room thermostat 80 to wire 94. Current also passes through the coils 50 and 46 because of their connection in parallel with the heating coil 57, whereupon the core 53 is lifted to open the supply of gas to the gas-tube 16 and sparking is produced between the spark terminals 19 and 20 for igniting the gas issuing from the tube 16'. At the same time the coils and 74 are energized to lift the armature 76 and rock the switch device 69 to the circuit-closing position shown for starting the burner-motor into operation, the circuits being as follows From the wire 93 to wire 95,

wire 97 ,coil 74, wire 102, wire 100, thence through switch device 58 and from wire 99 through the boiler thermostat and room thermostat to wire 94.- Also from wire 93 to wire 95, to wire 98 through coil 75 to'wire 105, wire 104, switch device 37, wires 103 and 100, switch device 58, and back through wire 99 to wire 94, it being understood that whereas the energizing of the coil 74 is effected when the coil 57 is energized, the energization of the coil 75 is dependent upon the switch 37 (Fig. 2) being closed.

The motor circuit thus established by closing switch 69 is as follows: From wire 93 to wire 95, motor 201, wire 101, switch 69, wire 100, switch 58, wire 99 and boiler and room thermostats 85 and to wires 99 and 94.

The burner-motor thus operating to discharge oil therethrough into the furnace, the oil is ignited by the flame at the gas tube 16 and the furnace is thus put into operation. The receptacle 23 of the switch mechanism 22 is thus subjected to the heat of the flame issuing from the burner with the result that the air in this receptacle expands and operates the switch device 37 to circuit-breaking position, thereby cutting out the coils 46, 50, 57 and 75, with the result of discontinuing the supply of gas to the tube 16 and sparking current to the sparking electrodes 19 and 20, in-

asmuch as the flow of current to these various through wire 95, wire 97, coil 74, wire 102,

wire 100, switch device 58 and wire 99 to wire 94.

So long as current continues to be supplied from the line wires 93 and 94 and oil continues to be supplied to the burner, and the temperature in the room in which thethermostat 80 is located does not rise to a predetermined de' gree and the pressure of the boiler does not rise above the predetermined degree, the various electrical devices referred to will remain in the conditions last described and the burner will thus continue in operation.

- Should, however, the flow of oil to the burner cease, or for any reason the burner fail to discharge oil into the furnace and failure of ignition thereof, occur, the apparatus will operate automatically to shut off the fiow of current to the motor 201; and should the flow of current to the motor be momentarily discontinued, as for example by someone opening, even momentarily, a switch in the line, no ourrent will flow to the burner-motor unless, and until, the means for supplying gas to the gas tube 16 and current to the sparking electrodes 19 and 20 are rendered operative to ignite the oil discharged by the burner in the beginning of the operation of the motor, thereby avoiding the accumulation of unignited gasified fuel in the furnace of such volume as might result in serious damage when ignited.

The apparatus is rendered capable of operating as stated by reason of the provision of the heat-controlled contactdevice 22 which is very responsive to variations in temperature and which in a comparatively small fraction of a minute, following the extinguishment of the flame at the burner, assumes circuit-closing. position and in doing so closes the circuit through the coils 46, 50, 57 and 75 thereby opening the device 18 to the flow of gas to the gas tube 16, producing sparking at the electrodes 19 and 20, heating the coil 57 and energizing the coil 75, the latter producing no effect as the armature 76 is already in raised position. The current continues to traverse these various coils until the thermostat member 64 has become suflicient-ly heated by the coil 57 to deflect to a position in which it releases the switch device 58 whereupon the latter drops to circuit-breaking position, thereby discontinuing the supplying of current to all of the electrical devices referred to,

whereupon both coils 74 and 75 of the relay become deenergized, and the switch device 69 rocks to circuit-breaking position thus breaking the burner-motor circuit, it being understood that the switch device 58 requires to be hand-set to again close the circuit therethrough after the thermostat member 64 has cooled sufliciently to position it for holding the switch device 58 in the raised position shown in Fig. 4.

Should the flow of current to the burner motor be momentarily arrested, coil 74 becomes deenergized and switch 69 opens and breaks motor-circuit and it is impossible for the motor to again start into operation, until the switch device 37, in the cooling of the receptable 23, returns to circuit-closing position (Fig. 4) whereupon the gas supplying means and the sparking means are caused to simultaneously operate with the burnermotor, following the resumption of the supplying current to the apparatus. It is thus impossible for a large volume of gas to accumulate in the furnace, to be thereafter ignited, with dangerous, or damaging, results.

It will, of course, be understood that when the temperature in which the room thermo stat 80 is located "rises above a predetermined degree, or the pressure in the boiler rises above a predetermined degree the main circuit will be broken, thus discontinuing the supplying of current to the burner motor;

and upon the dropping of the temperature orv pressure, as the case may be, below the premeans for operating the burner, ignition determined degree, the main circuit will be again closed and the apparatus started into operation as hereinbefore explained, it being understood that following the breaking of the circuit at either the thermostat 80- or 85 the mechanism 22 automatically moves to circuit-closing position by the cooling of re ceptacle 23. v-

It will also be understood that should, for any reason, the motor in starting fail to discharge oil into the furnace, following the closing of the circuit through the thermostats 80 and 85, the mechanism 22 will remain in circuit-closing position, thereby maintaining a flow of current thro h the heating coil. 57 which operates, by heating the thermostat 64 to effect the breaking of the circuit at the contact device 58.

among others is the advantage that high voltage current may be used throughout the system, the use of which results in positive control as compared with using low voltage, delicately operating, apparatus, and that burning out of the motor, should it failto start, is prevented.

While the use of gas ignited by an electric spark to ignite the oil is desirable, it will be understood that in some cases gas-supplying means may be omitted and the oil ignited directely by the electric spark.

While I have illustrated and described a particular construction embodying my invention, I do not wish tobe understood as intending to limit it thereto, as the same may be variously modified and altered without departing from the spirit of my invention.

. What I claim as new, and desire to secure by Letters Patent, is:

1. The combination with a burner, of means for operating the burner, electrical mechanism including a circuit controlling the actuation of said means, a switch controllin said circuit, a second switch controlling sai circuit, a second circuit, a third switch controlling said second circuit, means controlled by the heat produced by the burner for controlling said third switch, a fourth switch controlling said first circuit, an electro-magnet having two windings and controlling said first-named switch and operable only by energization of both of said windings but operating to hold said first-named switch in the position to which it is actuated by said magnet by current flowing through one winding only, said fourth switch controlling both of said windings and said third switch one only of said windings, and means controlled by said third switch for controlling said sec- I ond switch operating after the lapse of a predetermined length of time to condition said second switch for discontinuing the operation of said first-named means. i

2; The combination with a burner, of

means for the burner, electrical mechanism including a circuit controlling the actuation of said first-named means, a switch controlling said circuit, a second switch controlling said circuit,a second circuit, a third switch controlling said second circuit, means 'con-' said windings and said third switch one of said windings, means controlled bysaid third switch for controlling said second switch operating after the lapse of a predetermined length of time to conditionsaid second switch for discontinuing the operation of said firstnamed means, and means controlled by said fourth switch for controlling said ignition means.

3. The combination with a burner, of means for operating the burner, electrical mechanism including a circuit controlling the actuation of said means, a switch in said circuit, an electro-magnet controlling said switch and having two windings operable only by energization of both of said windings, but operating to hold said switch in the position to which it is actuated by said magnet by current flowing through one winding only,

a manually settable switch 'in'sai'd circuit, a third switch in said circuit, a second circuit, a fourth switch in said second circuit, a thermostatic element normally maintaining said second switch in c rcuit-closing position, a heating 0011 for cooperation with said ther- 'mostatic element, a pilot burner for said first named burner, means for controlling the flow of gas to said pilot burner, means for producing a flame at said pilot burner, circuit connections controlled by said third switch and said'fourth switch controlling said heat- 'ing coil and said gas supplying means and said flame producing means operating to heat said coil and supply gas to the pilotburner and ignite the same when said third and fourthswitches are closed, and deenergize the heating coil and discontinue theflow of gas to the pilot burner and the producing of flame thereat upon the breaking of the circuit at said fourth switch, said third switch controlling one only of said'windings.

4. The combination with a burner, of means for operating the burner, electrical mechanism including a circuit controlling the actuation of said means, a switch controlling said circuit, a second switch controlling said circuit, a second circuit, a third switch controlling said second circuit, means controlled by the heat produced by the burner for controlling said third switch, a fourth switch controlling said first circuit, an electro-magnet having separate windings and controlling said first-named switch, one of said windings, after the magnet is energized, serving to hold said first-named switch in the position to which it was actuated by said magnet, said- 5. The combination with a burner, of 2 means for operating the burner,electrical mechanism including a circuit controlling the actuation of said means, a switch controlling said circuit, a second switch controlling said circuit, a se ond circuit, a third switch controlling said second circuit, means controlled by the heat produced by the burner for controlling said third switch, a fourth switch controlling said first circuit, an electro-magnot having separate windings and controlling said first-named switch, one of said windings, after the magnet is energized, serving to hold said first-named switch in the position to which it was actuated by said magnet and controlled by said first-named switch, said third switch controlling such portion of the winding of said magnet as is required to be energized to energize the magnet to switch-actuating position, and means controlled by said third switch for controlling said second switch operating after the lapse of a predetermined length of time to 5 condition said second switch for discontinuing the operationof said first-named means OSCAR c. SOHRKOEDER. 

